Spring control for electrical measuring instruments.



E. P. NOYES.

SPRING CONTROL FOR ELECTRICAL MEASURING INSTRUMENTS. APPLICATION FILED OCT. 18. I915- 1,235,366. I PatentedJ111y3L1917.

Fig. 4

WITNESSES mvavroa cam; aaw/% illustrated-in th EDWARD PRESCOTT NOYES, OF FORT "MONROE, VIRGINIA.

SPRING CONTROL FOR ELECTRICAL MEASURING INSTRUMENTS.

i ,235,3oa.

Application filed October 1.8, 1915. Serial No. 56,559.

To all whom it may concern:

Be it known that I. "lnwaim lincst'o'i'r Novas, a citizen of the T'nited States. residing at Fort Monroe. in the county-ct Elizabeth City and State of Virginia, have invented anew Spring Control for Electrical Measuring Instruments. of which the following is a S])t('ll l(:ltl ()ll.

My invention relates to improvements in the spring control of those types of electrical measuring instruments the torque of wl'iich'increases at a greater rate than the current or voltage impressed upon them; and the objects of my improvement are, first, to provide a spring controlling device which will exert a counter torque such that the pointer will be deflected nearly uniformlv with uniform changes in the current or voltage impressed upon the instrument, thereby SGCllllILL a nearly uniform scale: secondfto afi'ord facilities for the proper adjustment of the pointer: and. third, to provide a means of counterhalancing the moving parts.

Tattain these objects by the mechanism accompanying drawing, in which Figure 1 is aside view of the mechanism as it appears disconnected from the rest of the instrl-nnent; Fig. 2. a bottom View of the, mechanism as it appears disconnected from the rest of the instrument: Fig. 3, a side view of'the mechanism connected to such parts of the instrument as it has any connection with: and Fig. 4. a top View of the mechanism and as much of the instrument it has any direct connection with, as it appears when the pointer is deflected through amiroxima'l'elv seventy five degrees.

Similar numbers refer to sumla-r parts throughout the several views.

The arm 1 supports one or more'springs 2 (two in the present instance) and is so mounted that it can he revolved a. few degrees about'the' axis.of the sta-fl 11. The

springs 2 may be of any form which exerts a counter force dir'gaftlv i'iroportional to its extension. mv nn-thodibeing to use helical srnrings. The inner ends of the springs 2 are; connected to the links -5 the-latter being connected to the l' earings 7 on the arm 4. -Thc. links 3 are coni'iterbalanctal by the welgli'tsb. thus rclievingthe springs of any ipart of their weight in any position of'the instrument. The counterbalancing weights 6 may be dispensed with when the Ami.

Specification of Letters Patent.

I a I I carried by said splndle. ant mg said secondary arm and; spring.

Patented July 31 1917.

The arm 1. and hence the pointer 10, may

be adjusted by means of the screw 5, secured to the case of the instrument 15, only a. broken section of the latter being shown. This screw 5 supports an eccentric pin 9, fitting into a slot 8 in the arm 1, any motion of the latter being connnunicated to the pointer 10 through the medium of the springs 2 and links 3. previously referred to: or the arm 1 may be adjusted by any other suitable means. that shown in the drawing forming no part of my present invention.

The staff 11. (only a part of which is shown) supports and is revolved by a movable coil. movable magnetic core, or other means of producing the necessary torque for deflecting the pointer. none of which are shown as they form no part of my presthat shown in the drawing forming no part of my presentinve'ntion.

The principle upon which my invention operates is as follows: i

As the pointer 10 is deflected from zero by the staff 11. the springs 2 oppose this motion at a constantlv increasing rate until the latter part of the scale is reached, when: the rate begins to decrease The counteri torque exerted by the springs 2 is not therefore uniform, but follows very closely th same law that the torque exerted by th instrument follows. and the result is the the pointer is deflected by very nearly tmi. form inc'rementswhen the current or ion-i .age impressed upon the instrument is va 'ed by uniform increments. thereby permitting nearly uniform divisions upon the scale 16.

I claim: 1. In a measuring insltriunent the combination with a supporthlig spindle, of a rotatably mounted spring upporting arm, a. spring carried by said arm. a secondary arm l a link connect- 2. In a measuringiinst-rutnent the combis i' ll 5! no i nation with a supporting spindle, of a spring-supporting arm adjustable about the axis of said spindle, a spring carried by said arm, a secondary arm carried by said spindle, and a link connecting said second a-ry arm and spring.

3. In a measuring instrument the combination with a supporting spindle, of a spring'supporting arm adjustable about the axis of said spindle, springs carried by said arm, secondary arms carried by the said spindle, and links connecting said second-' arm, springs carried by said arm, secondary arms carried by said spindle, andoppositely disposed links connecting said secondary a-rms and springs.

5. In a measuring instrument the combination with a supporting spindle, of a spring-supporting arm adjustable about the axis of said spindle, springs carried by the outer portions of" said spring-supporting.

arm, secondary arms carried by said spindle,

oppositely disposed links connecting said secondary arms and their respective springs in pairs, and counter-Weights mounted upon said links.

EDWARD PRESCOTT NOYES.

' Witnesses: v

PHILIP WILNER Hunos'ro'r, WILLIAM DAVID FRAZER. 

